<template>
  <div :style="{ paddingBottom: isShow ? '1.23rem' : '2.13rem' }" ref="cmtRef">
    <!-- 评论列表 -->
    <div class="cmt-list">
      <van-list
        v-model="loading"
        :finished="finished"
        finished-text="没有更多了"
        @load="theCommentList"
        offset="50"
        :immediate-check="false"
      >
        <!-- 评论的 Item 项 -->
        <div class="cmt-item" v-for="item in commentList" :key="item.com_id">
        <!-- 头部区域 -->
        <div class="cmt-header">
          <!-- 头部左侧 -->
          <div class="cmt-header-left">
            <img :src="item.aut_photo" alt="" class="avatar">
            <span class="uname">{{item.aut_name}}</span>
          </div>
          <!-- 头部右侧 -->
          <div class="cmt-header-right">
            <van-icon name="like" size="16" color="red" v-if="item.is_liking" @click="likeFn(false, item)" />
            <van-icon name="like-o" size="16" color="gray" v-else @click="likeFn(true, item)" />
          </div>
        </div>
        <!-- 主体区域 -->
        <div class="cmt-body">
          {{ item.content }}
        </div>
        <!-- 尾部区域 -->
        <div class="cmt-footer">{{ $timeAgo(item.pubdate) }}</div>
        </div>
      </van-list>
    </div>
    <!-- 底部添加评论区域 - 1 -->
    <div class="add-cmt-box van-hairline--top" v-if="isShow">
      <van-icon name="arrow-left" size="0.48rem" @click="$router.back()" />
      <div class="ipt-cmt-div" @click="isShow = false">发表评论</div>
      <div class="icon-box">
        <van-badge :content="commentCount" max="99">
          <van-icon name="comment-o" size="0.53333334rem" @click="handleScroll" />
        </van-badge>
        <van-icon name="star-o" size="0.53333334rem" />
        <van-icon name="share-o" size="0.53333334rem" />
      </div>
    </div>
    <!-- 底部添加评论区域 - 2 -->
    <div class="cmt-box van-hairline--top" v-else>
      <textarea
      placeholder="友善评论、理性发言、阳光心灵"
      v-focus
      @blur="handleBlur"
      v-model.trim="content"
      @keydown.enter="sendComment"
      ></textarea>
      <van-button type="default" :disabled="!content" @click="sendComment">发布</van-button>
    </div>
  </div>
</template>

<script>
import { getCommentList, likeComment, disLikeComment, sendCommentAPI } from '@/api/article'
export default {
  name: 'CommentList',

  data () {
    return {
      // 评论列表
      commentList: [],
      // 评论数量
      commentCount: 0,
      // 控制评论第一个盒子的展示
      isShow: true,
      // 评论内容
      content: '',
      loading: false,
      finished: false
    }
  },

  created () {
    this.theCommentList()
  },

  methods: {
    // 获取评论数据(与上拉刷新同用)
    async theCommentList () {
      const resp = await getCommentList(this.$route.query.aid, this.lastId || null, 10)
      const { results, total_count: totalcount, last_id: lastid } = resp.data
      // 如果后台没有数据了
      if (!results.length) {
        // 表明整个列表加载结束
        this.finished = true
        return
      }
      this.commentList = [...this.commentList, ...results]
      this.commentCount = totalcount || ''
      this.lastId = lastid
      // 更新loading状态为false
      this.loading = false
    },

    // 评论的点赞与取消赞
    async likeFn (flag, item) {
      try {
        // flag为true表示点赞，false表示取消点赞
        // 调接口发请求，把点赞状态同步到后台数据
        flag ? await likeComment(item.com_id) : await disLikeComment(item.com_id)
        // 直接对评论对象的is_liking取反即可
        item.is_liking = !item.is_liking
        // 成功的提示文字
        flag ? this.$toast.success('点赞成功') : this.$toast.success('已取消赞')
      } catch (error) {
        // 失败的提示文字
        flag ? this.$toast.fail('点赞失败') : this.$toast.fail('取消失败')
      }
    },

    // 点击评论图标滑动
    handleScroll () {
      // 需求：点击小图标让评论列表出现在可视区
      // 方式1：offsetTop + document.documentElement.scrollTop/window.scrollTo
      // 方式2：找到评论组的根元素 + scrollIntoView

      // 1.获取评论组件的根元素
      const el = this.$refs.cmtRef
      // 2.调用 scrollIntoView 方法
      el.scrollIntoView({
        // 添加滚动过渡动画
        behavior: 'smooth'
      })
    },

    // 发布评论
    async sendComment () {
      // 非空校验
      if (!this.content) return
      // 调接口发请求
      const resp = await sendCommentAPI(this.$route.query.aid, this.content)
      // 把后台返回的新的评论unshift到数组中
      this.commentList.unshift(resp.data.new_obj)
      // 数量++
      this.commentCount++
      // 清空并关闭表单
      this.content = ''
      this.isShow = true
    },

    // 文本域失焦
    handleBlur () {
      // 异步设置 isShow 为true
      setTimeout(() => {
        this.isShow = true
      })
    }
  }
}
</script>

<style scoped lang="less">
.cmt-list {
  padding: 10px;
  .cmt-item {
    padding: 15px 0;
    + .cmt-item {
      border-top: 1px solid #f8f8f8;
    }
    .cmt-header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      .cmt-header-left {
        display: flex;
        align-items: center;
        .avatar {
          width: 40px;
          height: 40px;
          background-color: #f8f8f8;
          border-radius: 50%;
          margin-right: 15px;
        }
        .uname {
          font-size: 12px;
        }
      }
    }
    .cmt-body {
      font-size: 14px;
      line-height: 28px;
      text-indent: 2em;
      margin-top: 6px;
      word-break: break-all;
    }
    .cmt-footer {
      font-size: 12px;
      color: gray;
      margin-top: 10px;
    }
  }
}
/*美化 - 文章详情 - 底部的评论页面 */
// 外层容器
.art-cmt-container-1 {
  padding-bottom: 46px;
}
.art-cmt-container-2 {
  padding-bottom: 80px;
}

// 发布评论的盒子 - 1
.add-cmt-box {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  box-sizing: border-box;
  background-color: white;
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 46px;
  line-height: 46px;
  padding-left: 10px;
  .ipt-cmt-div {
    flex: 1;
    border: 1px solid #efefef;
    border-radius: 15px;
    height: 30px;
    font-size: 12px;
    line-height: 30px;
    padding-left: 15px;
    margin-left: 10px;
    background-color: #f8f8f8;
  }
  .icon-box {
    width: 40%;
    display: flex;
    justify-content: space-evenly;
    line-height: 0;
  }
}

.child {
  width: 20px;
  height: 20px;
  background: #f2f3f5;
}

// 发布评论的盒子 - 2
.cmt-box {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 80px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 12px;
  padding-left: 10px;
  box-sizing: border-box;
  background-color: white;
  textarea {
    flex: 1;
    height: 66%;
    border: 1px solid #efefef;
    background-color: #f8f8f8;
    resize: none;
    border-radius: 6px;
    padding: 5px;
  }
  .van-button {
    height: 100%;
    border: none;
  }
}
</style>
